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Sasmono, R. Tedjo. "Transcriptional regulation of c-fms gene expression /." [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17479.pdf.
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John, Christopher Robert. "Gene expression associated with the evolution of C₄ photosynthesis." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709401.
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David, John M. "The control of apolipoprotein C-I gene expression during adipocyte differentiation." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 4.92 Mb., p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435920.
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Thirumalai, Avinash N. "Regulation of C-reactive Protein Gene Expression and Function." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etd/2467.
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Human C-reactive protein (CRP) is the prototypic acute phase protein whose serum concentration increases rapidly during inflammation. CRP is also associated with atherosclerosis; it is deposited at lesion sites where it may interact with modified lipoproteins. There are 2 major questions regarding CRP: 1. How is the serum concentration of CRP regulated? 2. What are the functions of CRP in atherosclerosis?
Our first aim was to determine the role of the constitutively expressed transcription factor Oct-1 in regulating CRP gene expression. We found that Oct-1 overexpression inhibited (IL-6+IL-1β)- induced CRP gene expression; maximal inhibition required the binding of Oct-1 to an octamer motif at (-59 to -66) on the CRP promoter. Oct-1 overexpression inhibited both (IL-6+IL-1β)- induced and C/EBPβ-induced CRP gene expression even when the Oct-1 site was deleted. These findings suggest that Oct-1 is a repressor of CRP gene expression that acts via binding to its cognate site on the CRP promoter as well as through indirect interactions with other promoterbound transcription factors.
Our second aim was to investigate the interaction of CRP with oxidized low density lipoprotein (ox-LDL). Acidic pH, a hallmark of atherosclerotic lesions, reversibly alters CRP structure and exposes a hidden binding site that enables CRP to bind ox-LDL. Using site-directed mutagenesis we constructed a CRP mutant (E42Q) that showed significant binding to ox-LDL at physiological pH. E42Q CRP required a less acidic pH for maximal binding and bound ox-LDL more efficiently than wild type CRP at any pH. We then examined if reactive oxygen species also induced CRP – ox-LDL interaction. H2O2-treated CRP bound ox-LDL at physiological pH. Like acidic pH, H2O2-treatment induced only a local structural change exposing the ox-LDL binding site. E42Q and H2O2-modified CRP are tools to study the function of CRP in animal models of atherosclerosis, which may not have an inflammatory environment sufficient to modify CRP and induce binding to atherogenic ox-LDL.
We conclude that Oct-1 is one of the critical regulators of CRP gene expression, and that CRP can be modified in vitro to convert it into an atherogenic LDL-binding molecule.
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Paradis, François William François William. "The expression of cellulomomas fimi cellulase genes in Brevibacterium lactofermentum and characterization of recombinant C. fimi B-glucosidase A from E coli." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30586.
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In the first part of this thesis, I describe the expression of C. fimi cellulase genes in the closely related Brevibacterium lactofermentum by generating a shuttle vector able to replicate selectively in the latter and carrying full length cellulase-encoding genes. The expression of those genes apparently originated from some unpredicted regulatory sequences, possibly located within the vector itself. The enzymatic activity was mostly found in the culture medium in B. lactofermentum indicating that the organism secreted the enzymes. The putative C. fimi promoter sequences did not function in B. lactofermentum, making difficult the analysis of their roles in expression of C. fimi cellulase genes.
In the second part of this thesis, I describe the characterization of a recombinant C. fimi exo-ϐ-1,4-glucosidase (CbgA) expressed in E. coli. The purified enzyme had a Mr of 183 kDa and hydrolysed various ϐ-glucosides with a preference for cello-oligosaccharides in the order C5>C4>C3>C2. The intact CbgA polypeptide was not required for enzymatic activity since removal of about 700 residues from the amino terminus did not reduce activity. The purified enzyme was used to raise polyclonal antibodies which in turn were used to identify the corresponding enzyme in C. fimi. During the fractionation of C. fimi ϐ-glucosidases, several enzymes hydrolyzing various ϐ-glucosides were isolated together with the native CbgA, which was present in the culture medium as part of a protein aggregate.
Part of the nucleotide sequence of the 7.2 kb insert was determined. Alignments of the N-terminal amino acid sequences of the purified CbgA and truncated polypeptides with the partial nucleotide sequence of the cloned C. fimi DNA showed that precise excision was responsible for the appearance of a truncated form of CbgA. Alignment of the amino-terminal sequence of a CbgA:CexCBD fusion peptide indicated that the pre-mature CbgA starts with a putative leader sequence of 49 amino acids which is followed by a region rich in Pro and Ala residues. Two GTG translational initiation codons followed by sequences resemblingprokaryotic ribosome binding sites and separated by a large open reading frame were identified from data obtained after in vitro site-directed mutagenesis of the most upstream initiation codon suggesting that internal re-initiation may occur and that upstream regulatory sequences had not been isolated.Medicine, Faculty of
Medical Genetics, Department of
Graduate
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Ball, Sarah Elizabeth. "A study of c-fms in myeloid leukaemias." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252976.
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Xue, Lin. "A VISUALIZATION TOOL FOR CROSS-EXPERIMENT GENE EXPRESSION ANALYSIS OF C. ELEGANS." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/472.
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Forty-six genomic gene expression studies of free living soil nematode C. eleganshave been published. To facilitate exploratory analysis of those studies, we constructed adatabase containing all the published C. elegans expression datasets. A Perl CGIprogram, called Microarray Analysis Display (MAdisplay), allows gene expressionclustergrams of any combination of entered genes and datasets to be viewed(http://elegans.uky.edu/gl/madisplay). Perl programs were used to preprocess the rawdata from different sources into a common format and to transform the data to displaythe expression changes relative to each experiment's controls. Three hundred lists ofgenes from figures and tables were extracted from the publications and made available inthe GeneLists database, which also contains Gene Ontology and KEGG gene lists. Weused these tools to examine in a systematic fashion the mean expression of gene lists inthe set of microarray and SAGE experiments. Seventy-nine percent of publicationderived gene lists show a strong expression change (p-value andlt;0.001) in more than oneexperiment with the median being fourteen out of the 127 experiments that are derivedfrom the forty-six publications. This indicates that groups of genes identified in onepublication typically show an expression effect in many other experiments.
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Voleti, Bhavya. "Mechanism of Transcriptional Regulation of C-Reactive Protein Gene Expression." Digital Commons @ East Tennessee State University, 2007. https://dc.etsu.edu/etd/2058.
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C-reactive protein (CRP) is an acute phase protein produced by hepatocytes whose serum concentration increases in inflammatory conditions including cardiovascular complications. Statins that are used in the treatment of cardiovascular diseases to reduce cholesterol also lower serum CRP levels. In human hepatoma Hep3B cells, CRP is induced in response to cytokines IL-6 and IL-1β. The objective of the study was to determine the mechanism of regulation of CRP gene expression in Hep3B cells in response to cytokines and to determine the effect of statins on CRP expression. Key findings of our research were: 1. IL-1β-activated NF-κB p50/p65 acted synergistically with IL-6-activated C/EBPβ in inducing CRP transactivation through the proximal CRP promoter. 2. A NF-κB site was localized in the proximal CRP promoter centered at position -69 overlapping the known OCT-1/HNF-1/HNF-3 sites. 3. The synergy between IL-6 and IL-1β in inducing CRP gene expression was partially mediated through the NF-κB site. 4. In the absence of C/EBPβ, a complex containing C/EBPζ and RBP-Jκ was formed at the C/EBP-p50-site. 5. Overexpressed C/EBPζ repressed both (IL-6+IL-1β)-induced and C/EBPβ-induced CRP expression. 6. OCT-1 repressed (IL-6+IL-1β)-induced CRP transactivation through the proximal CRP promoter. 7. Statins reduce cytokine-induced CRP gene expression at the transcriptional level. These findings led us to conclude that: 1. CRP transcription is determined by the relative levels of various transcription factors such as C/EBPβ, C/EBPζ, NF-κB and OCT-1 and their interaction with the proximal CRP promoter. 2. Inhibition of CRP transcription by statins is not due to an anti-inflammatory effect but due to the direct effect on CRP gene expression.
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Hachicha, Mohamed. "Regulation of C-C and C-X-C chemokine gene expression in synovial fibroblasts and peripheral blood neutrophils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ25241.pdf.
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Dörr, Katrin Zaragoza. "Molecular mechanisms of gene activation and gene expression mediated by CCAAT/enhancer binding proteins." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2008. http://dx.doi.org/10.18452/15873.
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Der Transkriptionsfaktor CCAAT/Enhancer-Binding Protein alpha (C/EBPa) koordiniert Proliferationshemmung und Differenzierung von myeloiden VorlŠuferzellen und Adipozyten. C/EBPa ist ein transkriptioneller Aktivator von abstammungspezifischen Genen und blockiert den Zellzyklus durch Repression von proliferationsfšrdernden E2F Zielgenen. Die hier gezeigten Daten zeigen, dass auch umgekehrt E2F die transkriptionelle und differenzierungsfšrdernde AktivitŠt von C/EBPa entgegenwirkt. Somit besitzen E2F-C/EBPa eine zentrale Schalterfunktion zwischen Proliferation und Differenzierung. Der Repressionsmechanismus durch E2F ist in mehreren Aspekten neuartig: Zum erstenmal wurde gezeigt, dass E2F einen anderen Transkriptionsfaktor reprimieren kann. E2F reprimiert die transkriptionelle AktivitŠt von C/EBPa ohne Bindung an cis-regulatorischen Elemente, sondern durch direkte Protein-Protein Interaktionen, die die Bindung von C/EBPa an DNA verhindern. Diese Form der transkriptionellen Repression geschieht unabhŠngig von "Pocket-Proteinen''". Patienten mit Akuter Myeloiden LeukŠmie (AML) weisen hŠufig eine gestšrte DNA Bindung von C/EBPa auf, welche ursachlich fŸr granulozitŠren Funktionsstšrungen sein kšnnte. Daher wŠre es wichtig zu analysieren ob E2F die DNA Bindung von C/EBPa in AML Patienten beeintrŠchtigt und ob auf E2F gerichtete Therapien granulozitŠre Reifung wiederherstellen. C/EBPa blockiert Zellproliferation durch vielseitigen Mechanismen. Hier wurde gezeigt, dass C/EBPa mit UBF1, dem Co-Aktivator der RNA Polymerase I, an chromosomalen Foci positioniert wird. Eine €hnlichkeit zu anderen fokalen Strukturen suggeriert, dass C/EBPa die Transkription von Polymerase I regulierten rRNA Gene reprimieren und somit ribosomale Biogenese beeintrŠchtigen kšnnte. Die Assoziation zwischen C/EBPa und UBF1 wird durch die Histon-Methyltransferase SUV39H1 stimuliert. Demnach kšnnte die antiproliferative Funktion von C/EBPa nicht nur auf der Regulierung von RNA Pol II-abhŠngiger Transkription, sondern auch auf der Repression von RNA Pol I regulierter rRNA Synthese basieren.The transcription factor CCAAT/Enhancer-Binding Protein alpha (C/EBPa) coordinates proliferation arrest and differentiation of myeloid progenitors and adipocytes. C/EBPa acts as a transcriptional activator of lineage specific genes and blocks the cell cycle by repressing transcription of E2F-regulated genes. Data presented here suggest that also inversely E2F interferes with the transcriptional activity of C/EBPa, counteracting C/EBPa-mediated differentiation processes. Thus, E2F-C/EBPa are part of a switch mechanism between proliferation and differentiation. The mechanism by which E2F suppresses C/EBPa-mediated transactivation is novel in several aspects. E2F acts as a co-repressor of another transcription factor, C/EBPa, without binding to cis-regulatory elements, but by direct protein-protein interactions that abolish the binding of C/EBPa to DNA. This mechanism of transcriptional repression occurs independent of pocket proteins. Disturbed DNA binding of C/EBPa is often observed in AML patients suggesting a causative role in granulocytic disorders. Thus, it would be of main interest to analyze whether E2F mediates disruption of C/EBPa''s DNA-binding in AML patients and whether therapies directed against E2F could restore granulocytic maturation. Despite the extensive knowledge of mechanisms involved in the inhibitory function of C/EBPa, it has not been addressed whether C/EBPa may impinge on cell proliferation by affecting the ribosomal biogenesis of a cell. This work demonstrates an association of C/EBPa to the RNA Pol I transcription factor UBF1, both proteins retained in large chromosomal foci. Similarities to other focal structures associated to UBF1, suggest that C/EBPa may repress transcription of Pol I-transcribed rRNA genes, and thus affect ribosomal biogenesis. The enrichment of C/EBPa at sites of UBF1 is induced by the histone methyltransferase SUV39H1. Thus, C/EBPa may not only control lineage commitment and cell proliferation by regulating genes transcribed by RNA Pol II, but also may act as a repressor of RNA Pol I mediated rRNA synthesis.
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Katile, Seriba Ousmane. "Expression of defense genes in sorghum grain mold and tagging and mapping a sorghum anthracnose resistance gene." Texas A&M University, 2007. http://hdl.handle.net/1969.1/85878.
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Sorghum grain mold and anthracnose are two major diseases of sorghum
(Sorghum bicolor) that constrain sorghum production worldwide. Grain mold is caused
by several species of fungi, but the two most common are Curvularia lunata and
Fusarium thapsinum. Isolates of these two species were used to inoculate panicles of
selected sorghum cultivars in green house and field experimentations. Panicles were
sprayed at the time of anthesis with conidial suspensions of the two fungal species
individually or in a mixture and with water to serve as a control. Samples were collected
48 hours after inoculation for RNA extraction. In greenhouse studies, four cultivars
(Tx2911, Sureno, SC170 and RTx430) were used while thirteen cultivars were grown in
the field experiments. Gene expression was measured for the following genes using real
time polymerase chain reactions (rt-PCR): PR10, β-glucanase, chitinase, thaumatin,
sormatin, phenyalanine ammonia lyase (PAL), obtusifoliol 14α-demethylase (Obtus),
antifungal protein (AFP), apoptosis related protein (Apop) and leucine rich repeat
(LRR).
Seed germination tests in field grown cultivars indicated that germination rates
for SC279-14E, SC660 and Sureno were not greatly influenced by grain mold. Covering
the panicles with bags served to protect them against grain mold pathogens. The seed
mycoflora test showed that Fusarium thapsinum was the most frequently recovered
species and there were more species present in non-covered panicles.
The response of sorghum cultivars to grain mold infection involves multiple
defense genes. Real time PCR used to study the expression of sorghum defense in greenhouse grown plants showed that mRNA encoding PR-10, a small 10 kDa protein,
was highly expressed in the glumes and spikelets of resistant cultivars Tx2911 and
Sureno and constitutively in leaves. The expression of some other defense genes like
beta-glucanase, chitinase and AFP was variable. Sormatin was not expressed. Expression
of β-glucanase, chitinase, and PR10 was higher in field than in greenhouse experiments.
A second area of research involved tagging of a resistance gene for sorghum
anthracnose. Three AFLP markers (Xtxa607, Xtxa3181 and Xtxa4327) and three SSRs
(Xtxp3, Xtxp55 and Xtxp72) were identified. These markers were loosely linked to the
resistance genes. The markers are located on linkage group B. The results suggest that
markers located 20-30 cM on one side or the other of those tested should provide useful
tags for the resistance gene.
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Melkoumian, Zaroui K. "Pharmacological regulation of c-myc gene expression in human breast cancer cells." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2218.
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Thesis (Ph. D.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains x, 152 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 119-149).
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Crossland, Nicola. "Expression of the 5-HTâ†2â†c receptor gene in schizophrenia." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393476.
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Chana, Jagdeep. "The prognostic and therapeutic significance of C-MYC expression in melanoma." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314348.
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Urwin, Nigel A. R. "Studies on the structure and expression of the isocitrate lyase gene of Chlorella fusca." Thesis, University of the West of Scotland, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254324.
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Choudhury, Monideepa. "Antisense oligodeoxynucleotide-mediated alterations in slow troponin C gene expression during myogenesis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24454.pdf.
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Chan, Io Long. "The Plasticity and Variation in Gene Expression during Development in C. elegans." eScholarship@UMMS, 2019. https://escholarship.umassmed.edu/gsbs_diss/1051.
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Organisms modulate their response to changing environmental conditions through changes in gene expression, and extensive variations in gene expression are prevalent among individuals even within a population. This widespread plasticity and variability of gene expression is thought to play roles in adaptation and drive novel phenotypes in species. Understanding the mechanisms that contribute to such variations requires the analysis of interactions between the genome and its environment and sequence variations within the genome. This work consists of two projects investigating the plasticity and variation of gene expression during post-embryonic development in the nematode C. elegans.
In the first study, I examined the response to changes in population density in developmentally arrested L1 larvae. I systematically characterized arrested L1 larvae from low to high densities using single-worm RNA-seq and uncovered that the density of resuspended L1 larvae regulates the expression of hundreds of mRNAs. Further analysis revealed that the physiological response to changes in density is rapid and signaled by a non-canonical daf-22 ascaroside independent pathway. In the second study, I investigated the evolution of gene expression within species using two genetically divergent C. elegans strains (N2 and CB4856). I carried out RNA-seq and allele-specific analysis across six different conditions and four developmental stages, and we examined gene expression divergence using the homozygous parent and F1 hybrid system. This work provides a new experimental model for studying the evolution of gene expression and a comprehensive view of gene expression variation during development in C. elegans.
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Khan, Sahar Jabeen. "The effect of hepatitis C virus protein expression on interferon specific gene expression in hepatocyte cell lines." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409088.
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Brügger, Lukas Emanuel. "Expression of the c-fos gene after magnetic stimulation of the rat brain /." Bern : [s.n.], 1996. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Engert, Christoph G. "A C. elegans histone methyltransferase promotes spermatocyte gene expression, spermatid production and fertility." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112432.
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Thesis: Ph. D., Massachusetts Institute of Technology, Computational and Systems Biology Program, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references.
To better understand the tissue-specific regulation of chromatin state in cell-fate determination and development, we defined the tissue-specific expression of all 36 lysine methyltransferase (KMT) genes by endogenous mRNA detection in C. elegans. We found that most KMTs are expressed in only one or two tissues and that the germline is the tissue with the most general KMT expression. We discovered that the germline-expressed C. elegans ortholog of mammalian PRDM9, SET-1 7, promotes fertility through gene regulation in primary spermatocytes. SET-17 drives transcription of spermatocyte-specific genes from four genomic clusters to promote spermatid production. SET-1 7 is concentrated in stable, chromatin-associated nuclear foci at actively transcribed gene clusters, which we term spermatocyte transcription bodies. Our results identify the spatially restricted function of a PRDM9 ortholog in spermatocyte transcription and we propose that the spatial organization of chromatin factors might be a conserved mechanism in tissue-specific control of transcription.
by Christoph G. Engert.
Ph. D.
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Carlén, Lina. "Characterization of psoriasis lesions by protein expression profiling /." Stockholm : Karolinska institutet, 2006. http://diss.kib.ki.se/2006/91-7140-808-8/.
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陳世安 and Sai-on Chan. "In vivo and in vitro studies on the regulation of C-KI-RAS expression in liver." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B30251813.
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Ohnmeiss, Amanda Sara. "ANALYSIS OF LIGHT-INDUCED IMMEDIATE-EARLY GENE EXPRESSION IN THE SUPRACHIASMATIC NUCLEUS." Kent State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=kent1247680456.
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Ku, Nam-On. "Inflammatory cytokine regulation of pentraxin genes and tissue- specific expression of the gene for mouse C-reactive protein /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487780393266327.
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Peake, Matthew. "Regulatory pathways involved in mechanical induction of c-fos gene expression in bone cells." Thesis, Keele University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392159.
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The regulatory pathways involved in the rapid response of the AP-I transcription factor component, c-fos, to mechanical load in human primary osteoblast-like (HOB) cells and the human MO-63 bone cell line were investigated using a four-point bending model. HOB and MO-63 cells showed up regulation of c-fos expression after I-hour loading on fibronectin and collagen type I substrates; however, MO-63 cells did not respond on laminin YIGSR substrates. It was suggested that RGD mediated integrin interactions might be non-essential for the mechanical induction of c-fos at certain time points as indicated by a lack of inhibition associated with ROD-peptide treatment (however, evidence of the inhibitory nature of soluble RGD-peptides at these time points may require further examination). β1 integrin mediated interactions are critical as induction was completely blocked by anti-β1 integrin antibodies. The role of calcium signalling pathways was demonstrated by blocking up regulation with addition of EGTA, which chelates extracellular Ca2+, and gadolinium, which inhibits stretch-activated channels. L-type calcium channels may also be contributory but not essential, as addition of the L-type channel blocker, nifedipine inhibited the response, but not completely. Further evidence for involvement of calcium pathways followed addition of the Ca2+ ionophore A-23187 that induced temporally identical up regulation without loading. Protein kinase (C) mediated pathways were also shown to be critical, as shown by abolition of the response following H7 -dichloride treatment. Prostaglandin signalling pathways were non-essential, but were implicated in maximising load induction of c-fos as indicated by indomethacin induced inhibition. C-fos promoter analysis indicated that the major CRE is not essential for mechanically induced transcriptional activation of c-fos. An SRE containing promoter fragment appears to play a key role in this induction but is also not essential, indicating that multiple response elements are required. These results therefore demonstrate the essential nature of calcium, integrin and protein kinase mediated pathways in the induction of the early transcriptional mechanoresponse of bone, which are mediated by multiple response elements in the c-fos promoter.
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Gilmour, Jane. "The role of GATA3 and c-maf in human T-cell cytokine gene expression." Thesis, King's College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427926.
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Socha, Amanda L. "Differential expression of an endogenous retrovirus in MAIDS susceptible (C57BL/6) versus resistant (BALB/C) mice /." Connect to online version, 2006. http://ada.mtholyoke.edu/setr/websrc/pdfs/www/2006/159.pdf.
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Destro, Maria Fernanda de Sousa Setubal. "Analise dos niveis de expressão dos membros da familia HOX de genes homeobox localizados nos loci B e C em mucosa oral normal e carcinoma espinocelular oral." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288726.
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Orientador: Ricardo Della ColettaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Genes homeobox transcrevem fatores de transcrição com participação importante na organogênese através do controle da proliferação e diferenciação celular. Dentre estes genes destacam-se os membros da família HOX de genes homeobox, os quais estão envolvidos em processos celulares cruciais como controle do ciclo celular, diferenciação e apoptose. Os genes HOX estão relacionados com o surgimento de diferentes tipos de neoplasias, incluindo cânceres de mama, ovário, próstata, rins, pulmão, pele e leucemias. Na cavidade oral a participação destes genes é desconhecida. O objetivo deste estudo foi comparar os níveis de expressão dos membros da família HOX de genes homeobox dos loci B e C entre amostras orais de mucosa normal e carcinoma espinocelular (CEC). Para a realização deste trabalho, amostras de mucosa oral normal de pacientes não expostos aos principais fatores de risco para o câncer oral (hábito de fumar e consumir bebidas alcoólicas) e amostras orais de mucosa normal e CEC provenientes do mesmo paciente foram submetidos a ensaios semi-quantitativos de transcriptase reversa-reação em cadeia da polimerase (RT-PCR) ¿duplex¿, utilizando-se primers para o gene controle GAPDH e primers específicos para cada um dos membros dos loci B e C. Em adição, os níveis de expressão destes genes foram analisados em uma linhagem de queratinócito normal (HaCAT) e em 4 linhagens celulares derivadas de CEC oral. As linhagens celulares de CEC oral expressaram todos os membros do loci C, sendo que os genes HOXC4, HOXC5 e HOXC6 apresentaram maiores níveis de expressão quando comparado com a linhagem HaCAT. HOXB13 foi expresso por todas as linhagens celulares de CEC oral. Os genes HOXB1, HOXB3, HOXB5, HOXB8 e HOXC12 não foram expressos por nenhuma das amostras de mucosa oral normal, independente da origem, e de CEC oral. O padrão de expressão dos genes HOX foi muito similar entre os dois grupos de mucosa oral normal. As expressões dos membros HOXB7, HOXC4, HOXC5, HOXC6, HOXC8, HOXC9, HOXC10 e HOXC11 foram significantemente maiores nas amostras de CEC oral comparado com amostras de mucosa oral normal. Os níveis de expressão dos membros HOXB2 e HOXC13 foram significantemente maiores nas amostras de CEC oral quando comparado com os níveis de expressão encontrados nas amostras de mucosa normal de pacientes livres de fatores de risco. Estes resultados sugerem que a expressão alterada de alguns membros da família HOX de genes homeobox pode estar associada com o desenvolvimento e/ou progressão do CEC oral
Abstract: Homeobox genes encode transcription factors with an important role during normal development by controlling cellular proliferation and differentiation. Among those genes, the HOX family is involved in crucial biological processes such as the control of the cell cycle, differentiation and apoptosis. HOX genes are related to many cancers, including those of the breast, ovary, prostate, kidney, lung, skin and leukemias. In the oral cavity, the role of those genes is unclear. The aim of this study was to compare the expression levels of HOX genes from loci B and C between normal oral mucosa and oral squamous cell carcinoma (SCC). Samples of normal oral mucosa and oral SCC obtained from the same patient, and samples of normal oral mucosa from patients without history of exposition to risk factors related to oral SCC (smoking habit and alcohol consumption) were analyzed by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) duplex method with specific primers for the control gene GAPDH and for each of the HOXB and HOXC members. Additionally, we analyzed the expression profile of those genes in a normal keratinocyte cell line (HaCAT) and 4 oral SCC cell lines. Oral SCC cell lines expressed all members of the locus C, and the expression of HOXC4, HOXC5 and HOXC6 was higher in those cell lines compared with HaCAT. Only HOXB13 was expressed for all oral SCC cell lines. None of the normal oral mucosa and oral SCC samples expressed HOXB1, HOXB3, HOXB5, HOXB8 and HOXC12. The HOX expression profile of the 2 groups of normal oral mucosa was quite similar. Regardless of the oral normal mucosa source, the expression of HOXB7, HOXC4, HOXC5, HOXC6, HOXC8, HOXC9, HOXC10 and HOXC11 was statistically higher in oral SCC samples. HOXB2 and HOXC13 were significantly overexpressed in oral SCC when compared with normal oral mucosa from patients without risk factors related to oral SCC. These results suggest that a dysregulated expression of HOX genes from clusters B and C may be related to the tumorigenesis and/or tumor progression of oral SCCs
Mestrado
Patologia
Mestre em Estomatopatologia
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Arda, H. Efsun. "C. Elegans Metabolic Gene Regulatory Networks: A Dissertation." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/479.
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In multicellular organisms, determining when and where genes will be expressed is critical for their development and physiology. Transcription factors (TFs) are major specifiers of differential gene expression. By establishing physical contacts with the regulatory elements of their target genes, TFs often determine whether the target genes will be expressed or not. These physical and/or regulatory TF-DNA interactions can be modeled into gene regulatory networks (GRNs), which provide a systems-level view of differential gene expression. Thus far, much of the GRN delineation efforts focused on metazoan development, whereas the organization of GRNs that pertain to systems physiology remains mostly unexplored.
My work has focused on delineating the first gene regulatory network of the nematode Caenorhabditis elegans metabolic genes, and investigating how this network relates to the energy homeostasis of the nematode. The resulting metabolic GRN consists of ~70 metabolic genes, 100 TFs and more than 500 protein–DNA interactions. It also includes novel protein-protein interactions involving the metabolic transcriptional cofactor MDT-15 and several TFs that occur in the metabolic GRN. On a global level, we found that the metabolic GRN is enriched for nuclear hormone receptors (NHRs). NHRs form a special class of TFs that can interact with diffusible biomolecules and are well-known regulators of lipid metabolism in other organisms, including humans. Interestingly, NHRs comprise the largest family of TFs in nematodes; the C. elegans genome encodes 284 NHRs, most of which are uncharacterized. In our study, we show that the C. elegans NHRs that we retrieved in the metabolic GRN organize into network modules, and that most of these NHRs function to maintain lipid homeostasis in the nematode. Network modularity has been proposed to facilitate rapid and robust changes in gene expression. Our results suggest that the C. elegans metabolic GRN may have evolved by combining NHR family expansion with the specific modular wiring of NHRs to enable the rapid adaptation of the animal to different environmental cues.
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Lichopoj, Katja [Verfasser]. "Functional expression of the C. elegans fat-1 gene in wild-type yeast / Katja Lichopoj." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2011. http://d-nb.info/1026069351/34.
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Burk, Janina, Claudia Gittel, Sandra Heller, Bastian Pfeiffer, Felicitas Paebst, Annette B. Ahrberg, and Walter Brehm. "Gene expression of tendon markers in mesenchymal stromal cells derived from different sources." Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-157823.
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Background: Multipotent mesenchymal stromal cells (MSC) can be recovered from a variety of tissues in the body. Yet, their functional properties were shown to vary depending on tissue origin. While MSC have emerged as a favoured cell type for tendon regenerative therapies, very little is known about the influence of the MSC source on
their properties relevant to tendon regeneration. The aim of this study was to assess and compare the expression of tendon extracellular matrix proteins and tendon differentiation markers in MSC derived from different sources as well as in native tendon tissue. MSC isolated from equine bone marrow, adipose tissue, umbilical cord tissue, umbilical cord blood and tendon tissue were characterized and then subjected to mRNA analysis by real-time polymerase chain reaction. Results: MSC derived from adipose tissue displayed the highest expression of collagen 1A2, collagen 3A1 and decorin compared to MSC from all other sources and native tendon tissue (p < 0.01). Tenascin-C and scleraxis
expressions were highest in MSC derived from cord blood compared to MSC derived from other sources, though both tenascin-C and scleraxis were expressed at significantly lower levels in all MSC compared to native tendon tissue (p < 0.01). Conclusions: These findings demonstrate that the MSC source impacts the cell properties relevant to tendon regeneration. Adipose derived MSC might be superior regarding their potential to positively influence tendon matrix reorganization.
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Mollica, Luigina. "Regulation of human endothelial cell protein C receptor gene (hEPCR) expression : role of a 5' enhancer." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436330.
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Armstrong, Kristin R. "Multiple Mechanisms Contribute to Regulation of Gene Expression in the C. elegans Excretory System." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1214071705.
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Ely, Heather Ashlie. "A mechanism for gonadotropin-releasing hormone induction of c-Fos gene expression in pituitary gonadotrope cells." Diss., [La Jolla, Calif.] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p1462104.
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Thesis (M.S.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed March 19, 2009). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 66-72).
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Russnak, Roland Hans. "Structure, expression and evolution of the 16 kilodalton heat shock protein gene family of C. elegans." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27521.
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Sequences coding for three related 16 kd heat shock proteins (hsps) of the nematode Caenorhabditis elegans were isolated and characterized. The extensive accumulation of hsp16 mRNA during heat stress facilitated the identification of two cDNAs, CEHS48 and CEHS41, which encoded hsp16 variants. These plasmids were selected by their ability to hybridize to mRNA which directed the synthesis of hspl6 in vitro, and were further characterized by sequence analysis.
Two-dimensional gel electrophoresis of hspl6 synthesized in vitro from mRNA selected by hybridization to either of the cDNAs under conditions of low stringency revealed the existence of at least five electrophoretic variants with significantly different isoelectric points.
The above cDNAs were used as specific probes to isolate recombinant bacteriophage containing C. elegans genomic DNA. Overlapping phage clones were used to define a region of approximately 30 kilobases. The genes coding for hsp16-48, previously identified by cDNA cloning, and for another 16 kd hsp designated hspl6-l were characterized by DNA sequencing. These two genes were arranged in a head-to-head orientation. Both the coding and flanking regions of these genes were located within a 1.9 kb region which was duplicated exactly to form a perfect 3.8 kb inverted repeat structure. This structure ended in unusual G + C-rich sequences 24 bp in length. The identity of the two arms of the inverted repeat at the nucleotide sequence level implied that the duplication event may have occurred relatively recently in evolution. Alternatively, gene conversion between the two modules could have maintained homology between the two gene pairs. Comparison of the hsp16-48 gene with its corresponding cDNA revealed the presence of a single, short intron. An intron of comparable length and in an analogous position was also found in the hsp16-1 gene. The introns separated variable and conserved regions within the amino acid sequences of the encoded heat shock proteins. A domain of approximatey 80 amino acids is contained within the conserved second exon and is homologous to a similar region in the small hsps of Drosophila, Xenopus, soybean and man as well as the a-crystallin protein of the vertebrate lens.
Each hsp16 gene contained a TATA box upstream of the start of transcription. Promoter sequences, which have been shown to be required for heat inducibility in various systems, were located upstream of either TATA box
Northern blot analysis showed that the hsp16-48 and hsp16-1 genes are expressed at levels approximately 20 - 40 fold lower than two closely related genes, hsp16-41 and hsp16-2, upon temperature elevation.Medicine, Faculty of
Biochemistry and Molecular Biology, Department of
Graduate
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Duarte, Tiago Pereira de Lacerda Costa. "Effects of vitamin C on DNA damage, iron homeostasis and gene expression profiling in human fibroblasts." Thesis, University of Leicester, 2006. http://hdl.handle.net/2381/29854.
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Vitamin C (ascorbic acid, AA) is an important antioxidant in human plasma. AA has, however, other important, non-antioxidant roles in cells. Of particular interest is its involvement in iron metabolism, since AA enhances dietary iron absorption, promotes Fenton reactions in vitro and was reported to have deleterious effects in individuals with iron overload. The mechanisms of AA-driven free radical generation from iron have been the subject of great discussion. However, whilst the AA-driven Fenton reaction is well established in test tube reactions, the relevance of this pro-oxidant chemistry in cells, tissues or organisms remains unclear. To understand whether AA has an overall antioxidant or pro-oxidant effect in cells, the present study investigated its ability to modulate iron homeostasis and iron-mediated oxidative injury in primary normal human diploid fibroblasts. Results show that AA increased the levels of intracellular catalytic iron and concomitantly modulated the expression of two well known iron-regulated genes, ferritin and transferrin receptor. Notably, treatment of confluent fibroblasts with physiologically relevant concentrations of AA was not harmful but sensitised cells towards iron-dependent, H2O2-induced DNA strand breakage and cell death. The possibility that AA regulates cellular function, through its effects on the intracellular redox state and/or on iron homeostasis, was also addressed by performing a genome- wide analysis of AA-induced gene expression in human fibroblasts. Results showed that AA stimulates quiescent cell populations to re-enter the cell cycle and proliferate. In summary, this work shows that AA increases iron availability and enhances ROS-mediated, iron-dependent damage in human cells. It is proposed that AA may exacerbate the deleterious effects of metals in vivo and promote normal tissue injury in situations associated with elevated ROS production. It is also suggested that AA may promote fibroblast activation during the process of wound healing, where quiescent dermal fibroblasts are required to readily undergo cell division.
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Veiga, Mariana Barçante. "Significance of low-abundance transcripts detected in Caenorhabditis elegans muscle SAGE libraries." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/860.
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Serial Analysis of Gene Expression (SAGE) on Caenorhabditis elegans RNA from FACS sorted embryonic body wall muscle cells has identified nearly 8000 genes expressed in nematode body wall muscle. Approximately 60% of these are genes are expressed at low levels (<5 tags/~50,000-100,000 tag library). Low-abundance transcripts have typically been overlooked since most are considered experimental or contamination errors. Consequently, research has been focused on transcripts that are most enriched in the particular tissue of interest. Here I focus on the analysis of low-expressed transcripts in the muscle SAGE libraries in order to investigate what percentage of these are in fact expressed in muscle and are not false positives. Most well characterized C. elegans body wall muscle genes are not expressed at low levels, therefore I anticipate that focusing on these rarely expressed genes will allow for the identification of muscle components that have been previously unrecognized.
RT-PCR was performed on RNA isolated from purified body wall muscle cells to initially estimate what fraction of these low abundance transcripts present in the SAGE data are indeed expressed in muscle. I examined 128 genes, of which 84 were represented by a single SAGE tag. From this initial list, 38% of the low-expressed transcripts were verified for their presence in body wall muscle. Subsequently, reporter GFP fusions were used to deduce if these low-expressed transcripts are indeed expressed in vivo within muscle. Of the low-expressed genes that tested positive via RT-PCR, 42% showed in vivo expression in body wall muscle. When the results from the RT-PCR and in vivo expression experiments are combined, I can extrapolate that at least 16% of low-expressed genes identified by the SAGE libraries are in fact expressed in muscle and are not false positives.
RNAi and knockout analysis were performed in order to investigate the role of low-expressed muscle genes in myofilament structure. RNAi results show that 14/34 (41%) of the genes screened had mild defects in myofilament organization. The SAGE libraries identified 6388 low-expressed transcripts, this work suggests that at least 16% (1022 genes) of these are in fact expressed in muscle and may reveal new components previously overlooked by other approaches.
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Moser, Bernhard. "Molecular cloning, characterization and expression of the endoglucanase C gene of Cellulomonas fimi and properties of the native and recombinant gene products." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29036.
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In addition to substrate-associated cellulases, Cellulomonas fimi secretes endoglucanases ( endo-1, 4-β-D-glucan glucanohydrolases, EC 3.2.1.4. ) which are recovered from the cellulose-free culture supernatant of cells grown on microcrystalline cellulose. Two such enzymes, C3.1 and C3.2 with Mrs of 130'000 and 120'000, respectively, were purified to homogeneity. The two endoglucanases were shown to share the same N-terminal amino acid sequence and to hydrolyze carboxymethylcellulose ( CMC ) with similar efficiencies ( 236u/mg protein for C3.1 and 367u/mg protein for C3.2 ).
The recombinant lambda vector L47.1-169 was identified from a C.fimi DNA-lambda library on the basis of hybridization with C3.1/2-specific oligonucleotide probes. The subclone pTZ18R-8 only moderately expressed CMCase activity. The 5'-terminus of cenC ( the gene coding for C3.1/2 ) was localized in the insert by Southern transfer experiments and nucleotide sequence analysis. Results from total C.fimi RNA-DNA hybrid protection analyses defined the boundaries of cenC in pTZ18R-8 and led to the tentative identification of -10 and -35 promoter sequences.
To improve the expression of cenC, its entire coding sequence, except for the start codon GTG, was fused in frame to the ATG codon of a synthetic ribosomal binding site ( PTIS ) and placed under the transcriptional control of the lac p/o system. Induction of the resulting clone ( JM101[pTZP-cenC] ) led to impaired growth in liquid cultures because overproduction of CenC inhibited cell division'" and eventually led to cell death. Analysis of cell fractions by SDS-PAGE revealed a dominant ( >10% of total cell extract proteins ), clone-specific protein with a Mr of approximately 140'000 which was found exclusively in the cytoplasmic fraction. Conversely, 60% of the total CMC-hydrolyzing activity was localized in the periplasmic fraction indicating that the export of CenC is required for maximal expression of endoglucanase activity.
Isolation of the cellulolytic activities from an osmotic shockate led to the purification to homogeneity of two recombinant cellulases, CenC1 and CenC2, with Mr of 130'000 and 120'000, respectively. Both enzymes hydrolyzed CMC with similar efficiencies ( 278u/mg protein for CenC1 and 390u/mg protein for CenC2 ). In addition, amino acid sequence analyses showed the two enzymes to have the same N-termini as the native enzymes and proved furthermore that the CenC leader peptide was functional in Escherichia coli.Science, Faculty of
Microbiology and Immunology, Department of
Graduate
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Woodfield, Helen Kathleen. "Engineering the genes and expression patterns required for C₄ photosynthesis into C₃ species." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648653.
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Burket, Christopher T. "Two genes, dig-1 and mig-10, involved in nervous system development in C. elegans." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-1115102-141010.
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Dace, Alexandra. "Recepteurs de triiodothyronine, produits de genes c-erb a, dans la differenciation adipocytaire des cellules ob 17 : interactions avec des recepteurs apparentes dans la famille des recepteurs nucleaires (doctorat)." Aix-Marseille 2, 1997. http://www.theses.fr/1997AIX20654.
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Young, Duprane Pedaci. "From In Vitro to In Vivo: Control of C-Reactive Protein Gene Expression by Cytokines." Cleveland, Ohio : Case Western Reserve University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1201365244.
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Ponzo, Marisa Grace 1980. "Gene expression profiling of Met receptor tyrosine kinase-induced mouse mammary tumors." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115881.
Full textAbstract:
Breast cancer is a heterogeneous disease comprised of distinct biological entities that correlate with diverse clinical outcomes. Gene expression profiling has divided this heterogeneity into luminal, ERBB2+ and basal molecular subtypes. Basal breast cancers are difficult to treat as they lack expression of candidates suitable for targeted therapies and are associated with poor outcome.Elevated protein level of the hepatocyte growth factor receptor, MET, is observed in 20% of human breast cancers and correlates with poor prognosis. However, the role of MET in mammary tumorigenesis is poorly understood. To address this, we generated a murine model that expresses weakly oncogenic mutants of Met (Metmt) in the mammary epithelium under the transcriptional control of the mouse mammary tumor virus promoter. We demonstrate that Metmt induces mammary carcinomas with diverse phenotypes and used gene expression microarrays to elucidate gene expression changes induced by Met. Since mammary tumors contained variable contents of epithelium and stroma, we used laser capture microdissection to procure epithelial cells for microarray analysis. Based on immunohistochemistry and expression profiling, we show that Metmt produces tumors with luminal or basal characteristics. From hierarchical clustering, Metmt-induced basal tumors clustered with murine models that share features of epithelial to mesenchymal transition and human basal breast cancers. Moreover, Metmt basal tumors clustered with human basal breast cancer. The status of MET among the human breast cancer subtypes has not previously been addressed. We demonstrate that MET levels are variable across molecular subtypes but show elevation in the basal subtype and correlates with poor outcome. We used a candidate gene approach derived from microarray data to gain an understanding of signals required for Met-dependent tumorigenesis. We investigated Nck adaptor proteins and demonstrate a role for Nck in cell motility and actin dynamics of Met-dependent breast carcinoma cells and show elevated expression in human basal breast cancers. By generating a unique mouse model in which Met is expressed in mammary epithelia, with the examination of MET levels in human breast cancer, we have established a novel link between MET and basal breast cancer. This work identifies poor outcome basal breast cancers that may benefit from anti-MET therapies.
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Marti, Marimon Maria Eugenia. "3D genome conformation and gene expression in fetal pig muscle at late gestation." Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0099.
Full textAbstract:
Dans le secteur de l’élevage porcin, les truies ont été sélectionnées pendant des décennies pour leur prolificité afin de maximiser la production de viande. Cependant, cette sélection a été associée à une mortalité plus élevée des nouveau-nés. Dans ce contexte, le muscle foetal squelettique est essentiel à la survie du porcelet, car il est nécessaire pour les fonctions motrices et la thermorégulation. Par ailleurs, la structure tridimensionnelle du génome s'est avérée jouer un rôle important dans la régulation de l'expression génique. Ainsi, dans ce projet, nous nous sommes intéressés à la conformation 3D du génome et l'expression des gènes dans les noyaux des cellules musculaires porcines à la fin de la gestation. Nous avons initialement développé une approche originale dans laquelle nous avons combiné des données transcriptomiques avec des informations de localisations nucléaires (évaluées par 3D DNA FISH) d'un sous-ensemble de gènes, afin de construire des réseaux de gènes co-exprimés. Cette étude a révélé des associations nucléaires intéressantes impliquant les gènes IGF2, DLK1 et MYH3, et a mis en évidence un réseau de gènes interdépendants spécifiques du muscle impliqués dans le développement et la maturité du muscle foetal. Nous avons ensuite évalué la conformation globale du génome dans les noyaux musculaires à 90 jours et à 110 jours de gestation en utilisant la méthode de capture de conformation de chromatine à haut débit (Hi-C) couplée au séquençage. Cette étude a permis d'identifier des milliers de régions génomiques présentant des différences significatives dans la conformation 3D entre les deux âges gestationnels. Fait intéressant, certaines de ces régions génomiques impliquent les régions télomériques de plusieurs chromosomes qui semblent former des clusters préférentiellement à 90 jours. Plus important, les changements observés dans la structure du génome sont associés de manière significative à des variations d'expression géniques entre le 90ème et le 110ème jour de gestationIn swine breeding industry, sows have been selected for decades on their prolificacy in order to maximize meat production. However, this selection is associated with a higher mortality of newborns. In this context, the skeletal fetal muscle is essential for the piglet’s survival, as it is necessary for motor functions and thermoregulation. Besides, the three-dimensional structure of the genome has been proven to play an important role in gene expression regulation. Thus, in this project, we have focused our interest on the 3D genome conformation and gene expression in porcine muscle nuclei at late gestation. We have initially developed an original approach in which we combined transcriptome data with information of nuclear locations (assessed by 3D DNA FISH) of a subset of genes, in order to build gene co expression networks. This study has revealed interesting nuclear associations involving IGF2, DLK1 and MYH3 genes, and highlighted a network of muscle specific interrelated genes involved in the development and maturity of fetal muscle. Then, we assessed the global 3D genome conformation in muscle nuclei at 90 days and 110 days of gestation by using the High-throughput Chromosome Conformation Capture (Hi¬ C) method. This study has allowed identifying thousands of genomic regions showing significant differences in 3D conformation between the two gestational ages. Interestingly, some of these genomic regions involve the telomeric regions of several chromosomes that seem to be preferentially clustered at 90 days. More important, the observed changes in genome structure are significantly associated with variations in gene expression between the 90th and the 110th days of gestation
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Bonifaz, Peña Vania Elvira. "Effects of Silymarin on Hepatitis C Virus and Heme Oxygenase-1 Gene Expression in Human Liver Cells." Thesis, Universidad de las Américas Puebla, 2007. http://catarina.udlap.mx/u_dl_a/tales/documentos/mbt/bonifaz_p_ve/.
Full textAbstract:
Background: Hepatitis C virus (HCV) infection is a global medical problem. The current
standard of care for chronic hepatitis C (CHC) is pegylated interferon plus ribavirin
therapy, but this treatment is expensive, has significant side effects and, at best, is only
50% effective. Silymarin, the main active ingredient of milk thistle, is a natural
antioxidant that is used by patients with CHC, although its efficacy for decreasing HCV
levels or ameliorating CHC remains uncertain. HCV infection is associated with
increased hepatic oxidative stress, and one of the antioxidant enzymes which protects
cells against this stress is heme oxygenase-1 (HO-1). Methods: We investigated the
effects of silymarin on HCV and HO-1 gene expression in wild type Huh-7 cells, as well
as two HCV replicon cell lines, CNS3 and 9-13 cells. Results: Silymarin (100 and 200
μM) down-regulated HCV core mRNA (by 20% - 36%) and protein (by 30%-60%) in
CNS3 cells. In contrast, silymarin did not decrease HCV NS5A mRNA or protein
expression in treated 9-13 cells; in fact, it increased NS5A mRNA levels by two fold.
HO-1 mRNA was up-regulated (60%-400%) by silymarin in Huh-7, CNS3 and 9-13
cells. To explore the mechanism by which silymarin up-regulates HO-1 mRNA, we
measured the levels of Bach1 and Nrf2 transcription factors. Bach1 and Nrf2 mRNA
levels were not affected by silymarin treatment in Huh-7 cells. In CNS3 and 9-13 cells,
there was no clear relationship between silymarin-induced changes in Bach1 and Nrf2
and the induction of HO-1 mRNA. Silymarin do not down-regulate HCV core protein
through the Jak-Stat pathway. Conclusions: Silymarin significantly down-regulates HCV
core mRNA and protein in CNS3 cells. The effect of silymarin to down-regulate HCV
core is not related to changes in the Jak-Stat signaling pathway. The levels of the
antioxidant enzyme HO-1 are up-regulated by silymarin, but the precise mechanism by
which silymarin up-regulates HO-1 mRNA levels in these cell lines remains unknown.
These and other recent results suggest that silymarin is of benefit in CHC, although
prospective, randomized, controlled-trials are needed to be certain.
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Lomri, Nour-Eddine. "Isolement et caracterisation de l'adn#c de la cabp 28k de rat : expression et evolution du gene." Paris 7, 1989. http://www.theses.fr/1989PA077085.
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Isolement de l'adn complementaire de la calbindine-d28k (cabp28k), regulation par le cholecalciferol (dihydroxy-1,25), expression au niveau du systeme nerveux central et des reins et evolution moleculaire du gene
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Chakraborty, Atanu. "Mechanism Of mom Gene Transactivation By Transcription Factor C Of Phage MU." Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/275.
Full textAbstract:
Regulation of transcription initiation is the major determining event employed by the cell to control gene expression and subsequent cellular processes. The weak promoters, with low basal transcription activities, are activated by activators. Bacteriophage Mu mom gene, which encodes a unique DNA modification function, is detrimental to cell when expressed early or in large quantities. Mu has designed a complex, well-controlled and orchestrated regulatory network for mom expression to ensure its synthesis only in late lytic cycle. The phage encoded transcription activator protein C activates the gene by promoter unwinding of the DNA and thereby recruiting of RNAP to the promoter.
C protein functions as a dimer for DNA binding and transcription activation. Mutagenesis and chemical crosslinking studies revealed that the leucine zipper motif, and not the coiled coil motif in the N terminal region, is responsible for C dimerization. The DNA binding domain of C is a HTH domain which is preceded by the leucine zipper motif. The C protein is one of the few examples in the bacterial proteins containing both leucine zipper and HTH domain.
Most of the transcription activators either influence initial binding of RNAP or conversion of closed to open complex formation. Very few activators act at subsequent steps of promoter-polymerase interaction. Earlier studies showed high level of transcription from a mutant mom promoter, tin7. Addition of C further increased transcription from Ptin7 indicating that C may have a role beyond polymerase recruitment. Each steps of transcription initiation have been dissected using the Ptin7 and a positive control (pc) mutant of C, R105D. The results revealed multi-step transcription activation mechanism for C protein at Pmom. C recruits RNAP at Pmom and subsequently increases the productive RNAP-promoter complex and enhances promoter clearance.
To further understand the C mediated transactivation mechanism, interaction between C and RNAP was assessed. C interacts with holo and core RNAP only in presence of DNA. Positive control mutants of C, F95A and R015D, were found to be compromised in RNAP interactions. These mutants were efficient in RNAP recruitment to Pmom but do not enhance promoter clearance. Trypsin cleavage protection experiment indicated that probably C protein interacts with b¢ subunit of RNAP. Interaction between C and RNAP appears to enhance the formation of productive RNAP-promoter complex leading to promoter clearance.
The connection between activator-polymerase interaction and transcription activation is well documented where the recruitment of RNAP is influenced. In case of activators acting at post recruitment steps of initiation, the role of polymerase contact is poorly understood. Our study shows that activator-polymerase interaction can lead to increased promoter clearance at Pmom by overcoming abortive initiation.
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Albarqi, Mennatallah M. Y. "INSIGHTS INTO HOW THE 3´UTR MEDIATES EXPRESSION OF A CONSERVED RNA-BINDING PROTEIN AND CONTRIBUTES TO GERMLINE DEVELOPMENT IN C. ELEGANS." eScholarship@UMMS, 2021. https://escholarship.umassmed.edu/gsbs_diss/1156.
Full textAbstract:
Maternal mRNA regulation is essential to germline and embryo development in metazoans. Over the past few decades, it has become clear that many RNA-binding proteins (RBPs) containing highly conserved RNA-binding domains orchestrate spatiotemporal expression pattern of germline and embryonic genes to control gametogenesis and embryogenesis in the nematode Caenorhabditis elegans. These RBPs bind regulatory elements situated primarily in the UTRs of their target mRNAs to regulate expression by influencing transcript stability or translational efficiency. The 3´UTR is the main determinant of patterned expression in the germline of C. elegans. MEX-3 is a KH-domain RBP that is required for anterior cell fate specification and maintenance of germ cell totipotency. MEX-3 is expressed in mitotic germ cells, maturing oocytes, and early embryos. MEX-3 is absent in the meiotic pachytene region as well as the diplotene loop region. The 3´UTR of mex-3 is sufficient to confer MEX-3’s expression to a transgenic reporter. Here, I assessed the importance of the endogenous 3´UTR of mex-3 to MEX-3’s expression pattern and function using CRISPR/Cas9 mutagenesis followed by molecular and phenotypic analysis. 3´UTR deletion allelic series demonstrated that the endogenous 3´UTR of mex-3 is indeed required for MEX-3’s pattern in the germline in vivo. I identified regions of the 3´UTR that contribute to repression of MEX-3 in different regions of the germline. Surprisingly, the 3´UTR was dispensable for viability. However, several 3´UTR deletions exhibited reduced fertility. Analysis of the transcriptome of these mutants revealed that the 3´UTR deletions altered expression of soma-specific genes, consistent with MEX-3’s role in repressing somatic gene programs. These data sets also showed that mex-3 mRNA levels do not correlate with MEX-3 protein levels.
In order to determine which germline RBPs regulate expression of mex-3 through its 3´UTR, I used RNAi to knock down several candidate RBPs including three that were previously shown to regulate expression of MEX-3. My RNAi studies showed that GLD-1, LIN-41, and OMA-1/2 repress expression of mex-3 through its 3´UTR in the meiotic pachytene region, diplotene loop region, and oocytes in the proximal end, respectively. Furthermore, I have identified DAZ-1, an RRM-containing RBP, as a novel repressor of MEX-3 expression in the distal mitotic germ cells. Using RNAi, I demonstrated that poly(A) tail length control and the translation initiation factor IFE-3 contribute to MEX-3’s expression in the germline. Poly(A) polyadenylation and deadenylation cycles govern expression of mex-3 in the distal mitotic germ cells, while IFE-3 contributes to repression of mex-3 in the meiotic pachytene region, presumably by control of translation initiation. Using high throughput sequencing-based poly(A) tail assay, I have shown that the poly(A) tail length distribution of mex-3 mRNA shifts towards shorter tails in the mex-3 3´UTR deletion mutants with reduced fertility phenotypes. Our study is the first as far as we know to address the importance of an endogenous 3´UTR to in vivo expression and function in C. elegans germline. It will be interesting to determine how different RBPs and cis-regulatory elements orchestrate the spatiotemporal expression pattern of a single germline gene. It will also be interesting to assess whether other germline 3´UTRs are similarly dispensable for viability, and if so, what role do 3´UTRs play in enhancing reproductive success.
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Antunes, Alberto Azoubel. "O papel dos genes do pepsinogênio C (PGC) e do antígeno de membrana específico da próstata (PSMA) no diagnóstico do câncer da próstata." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/5/5153/tde-18122008-105156/.
Full textAbstract:
INTRODUÇÃO: O diagnóstico do câncer de próstata em pacientes com níveis séricos do antígeno prostático específico persistentemente elevados após biópsia prostática negativa representa um grande desafio para urologistas e patologistas. A baixa especificidade do antígeno prostático específico e a baixa sensibilidade da biópsia prostática guiada por ultra-som são os maiores obstáculos observados na prática clínica. Apesar do uso de diversos métodos para prever a presença de câncer na glândula, nenhum deles tem precisão absoluta, obrigando os pacientes a realizar novas biópsias. Neste contexto, a descoberta de novos marcadores diagnósticos para o câncer da próstata tornase necessária. OBJETIVO: Avaliar o valor diagnóstico da expressão de seis genes no tecido prostático de pacientes com câncer de próstata clinicamente localizado. MÉTODOS: O estudo consistiu na análise de 50 pacientes com diagnóstico de câncer da próstata, submetidos à prostatectomia radical por doença localizada. A seleção dos genes foi baseada em um estudo prévio que utilizou a tecnologia de microarray (Agilent Technologies 44k whole human genome, two-color) em pacientes com câncer de próstata, divididos de acordo com as características clínico-patológicas. Entre os 4.147 genes com expressão diferenciada entre os casos de câncer de próstata, seis genes (PSMA, TMEFF2, GREB1, TH1L, IgH3 e PGC) foram selecionados. Estes genes foram então testados quanto a seu valor diagnóstico no câncer da próstata através da técnica de reação em cadeia da polimerase quantitativa com transcriptase reversa. Na primeira etapa do estudo, amostras de tecido maligno de 33 pacientes com câncer de próstata foram avaliadas. O grupo controle foi composto de nove pacientes com hiperplasia benigna da próstata. Na segunda etapa do estudo foram analisadas amostras de tecido benigno dos demais 17 pacientes com câncer da próstata. O mesmo grupo controle foi utilizado para comparação. RESULTADOS: A análise demonstrou que o PSMA estava super-expresso (em média nove vezes) e o PGC sub-expresso (em média de 1,3 x 10-4 vezes) no tecido neoplásico de todos os casos de câncer quando comparados com os casos de hiperplasia benigna. Os demais genes demonstraram um padrão de expressão variado, não permitindo a diferenciação entre os tecidos malignos e benignos. Quando estes resultados foram testados no tecido prostático benigno dos pacientes com câncer, o PGC manteve o mesmo padrão de expressão em todos os casos e o PSMA, apresentou-se super-expresso em 88% dos pacientes (média de 12 vezes), em relação aos casos de hiperplasia benigna. CONCLUSÃO: A combinação da super-expressão do PSMA e sub-expressão do PGC no tecido prostático pode representar uma evidência objetiva de presença de Cap. Análises clínicas prospectivas adicionais são necessárias para confirmar estes resultadosIntroduction and objective: Prostate cancer (PCa) diagnosis in men with persistently increased PSA after a negative initial prostate biopsy has become a great challenge for urologists and pathologists. Despite the use of several methods to increase the sensitivity of prostate biopsy, the false-negative rates remain substantial, leading many patients to undergo repeated procedures. We analyzed the diagnostic value of six genes in the prostatic tissue of patients with clinically localized PCa, in order to predict the presence of cancer. Methods: The study was comprised by 50 patients with clinically localized PCa who underwent radical prostatectomy. Gene selection was based on a microarray analysis of patients with PCa. Among the 4,147 genes with different expressions between two groups, six genes (PSMA, TMEFF2, GREB1, TH1L, IgH3 and PGC) were selected. These genes were tested for its cancer diagnostic role using the quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) method. In the first part of the study, malignant tissue samples from 33 patients were analyzed, and in the second part we analyzed benign tissue samples of the other 17 patients with PCa. The control group was comprised of prostatic tissue samples of patients with benign prostatic hyperplasia (BPH). Results: The analysis of malignant prostatic tissue by qRTPCR showed that PSMA was over-expressed (mean nine times) and PGC was under-expressed (mean 1.3 x 10-4 times) in all cases when compared to BPH. The other four tested genes showed a variable expression pattern not allowing a differentiation between benign and malignant cases. When we tested these results in the benign prostate tissues from patients with PCa, PGC maintained the expression pattern, and PSMA, despite over-expression in most cases (mean 12 times), two cases (12%) presented under-expression. Conclusions: PGC under-expression and PSMA over-expression in the tissue may represent an objective evidence of prostate cancer and constitute a powerful adjunctive method in patients with negative prostate biopsy. Further prospective clinical analyses are necessary to confirm theses results
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Barnes, Calvin Langston Toure. "C-mpl Expression in Osteoclast Progenitors: A Novel Role for Thrombopoietin in Regulating Osteoclast Development." Yale University, 2006. http://ymtdl.med.yale.edu/theses/available/etd-06262006-123750/.
Full textAbstract:
A new paradigm has evolved in which multiple regulatory interactions between the skeletal and hematopoietic systems have been identified. Previous studies have demonstrated that megakaryocytes (MK) play a dual role in skeletal homeostasis by stimulating osteoblast proliferation and simultaneously inhibiting osteoclast (OC) development. Here we identify a novel regulatory pathway in which the main MK growth factor, thrombopoietin (TPO), directly regulates osteoclastogenesis. To study the role of TPO in OC development, spleen or bone marrow (BM) cells (2x10[exponent]6 cells/ml) or BM macrophages (BMM, 1x10[exponent]5 cells/ml) from C57BL/6 mice , as a source of OC precursors, were cultured with M-CSF (30 ng/ml) and RANKL (50 ng/ml) to induce OC formation. TPO (0.1-1000 ng/ml) and/or primary MK (0-0.5%), derived from C57BL/6 fetal livers, were titrated into these cultures and OC were identified as tartrate resistant acid phosphatase positive (TRAP+) giant cells with >3 nuclei. There was a significant, up to 15-fold reduction in OC formed when MK were added to all OC generating cultures, p < 0.001. Moreover, if OC generating cultures did not contain MK or MK progenitors, TPO treatment significantly enhanced OC formation up to six-fold, p < 0.01. This data demonstrates that MK are responsible for the inhibition of OC formation and that in cultures containing MK or MK progenitors such as BM or spleen cells, that TPO acts indirectly to inhibit OC formation by stimulating megakaryopoiesis, whereas in the absence of MK or MK progenitors TPO directly enhances OC formation. This conclusion is further supported by Real-Time PCR data which demonstrates that OC progenitors express c-mpl, the TPO receptor, albeit at low levels when compared to expression of c-mpl on MK. Finally, we have begun to dissect the c-mpl signaling pathway in OC progenitors. We have found that TPO induces tyrosine phosphorylation of several specific cellular proteins in the JAK/STAT pathway. Thus, TPO acts in a somewhat paradoxical manner by inhibiting OC formation through the stimulation of MK, while simultaneously playing a direct role in enhancing osteoclastogenesis.